They conclude that minced banana peel performs better than an array of other purification materials, such as coconut fiber and peanut shells.

Gustavo Castro, Ph.D., Universidade Estadual Paulista in São Paulo, and his colleagues note that mining processes, runoff from farms, and industrial wastes can all put heavy metals, such as lead and copper, into waterways. Current methods of removing heavy metals from water are expensive, and some substances used in the process are toxic themselves.

Previous work has shown that some plant wastes can remove these toxins from water. In this study, the researchers wanted to find out whether minced banana peels could also act as water purifiers.

The researchers found that minced banana peel could quickly remove lead and copper from river water as well as, or better than, many other materials. A purification apparatus made of banana peels can be used up to 11 times without losing its metal-binding properties, they note. The team adds that banana peels are very attractive as water purifiers because of their low cost and because they don’t have to be chemically modified in order to work.

The authors acknowledge funding from the São Paulo Research Foundation.